1. Technical Field
The present disclosure relates to a method for preparing cathode active materials of batteries and, particularly, to a method for preparing a cathode active material of a lithium battery.
2. Description of Related Art
Lithium transition metal oxides are currently used as cathode active materials for lithium-ion batteries, such as spinel type lithium manganese oxide (e.g. LiMn2O4), olivine type lithium iron phosphate (e.g. LiFePO4), and layered type lithium cobalt oxide (e.g. LiCoO2). LiCoO2 is a commonly used cathode active material in commercial lithium ion batteries, and has a stable structure and a high capacity. However, the high cost, toxicity, and limited abundance of cobalt have been recognized to be disadvantages of LiCoO2. As a result, alternative cathode active materials have attracted much interest. One promising candidate is LiMn2O4. LiMn2O4 has the advantages of low-cost, environmental friendliness, good safety, and high abundance.
However, the capacity lost during cycling is the biggest disadvantage of the Spinel LiMn2O4. Shu-Juan Bao et al. have compared the LiMn2O4 made from different manganese sources (Morphology and electrochemistry of LiMn2O4 optimized by using different Mn-sources, Journal of Power Sources 164 (2007) 885-889), and found the LiMn2O4 synthesized by using MnOOH as the manganese source has a relatively good cycle ability and high-rate capability. However, in the article, the LiMn2O4 is prepared by heating or sintering several times. To prepare LiMn2O4, MnOOH and LiNO3 are first mixed and grinded, and then annealed at 260° C. for 4 hours in air to form a precursor. After cooling and grinding, the precursor was calcined at about 610° C. for about 2 hours, and then calcined again at about 750° C. for about 12 hours, followed by slowly cooling to room temperature. The multi steps of thermal treating are complicated and disadvantageous for industrialized utilization.
What is needed, therefore, is to provide a simple and low cost method for preparing the cathode active material of a lithium battery suitable for mass production.